>Hello! I?m new to this reflector
hope the pool of experience can help me
>with a question:
>
>Five months ago I bought a new Ameritron AL-80B/X (/X=the export version:
>240-volts with 12 and 10m enabled). Unfortunately, so far, two 3-500Z?s
>(Amperex) have failed with grid-filament shorts.
>
>I?ve read the archives and know that this is a common problem
but is it a
>tube quality issue, or something about the amp
perhaps a parasitic or
>filament current inrush problem? Either way I?ve lost confidence in both
>Amperex 3-500Zs and the AL-80B.
It's not the fault of Amperex. Eimac and Penta 3-500Zs have the same
problem unless appropriate measures are used to decrease vhf-gain. The
tradeoff is c. 2% less power out at 27 - 29MHz. The root of the problem
is that there is no tube or transistor that does not have some feedback
C. What is the measured resistance of the parasitic suppressor in your
AL-80B ?
- RE: your 1kW requirement: In order to do 1kW linearly, a 3-500Z
needs a 4kV anode supply.
cheers, Rod.
>I want to dump the unit and get something
>more reliable.
>
>I?d appreciate the list?s recommendations for a simple, RELIABLE 1 Kw pep
>HF amp that does not use 3-500Zs and retails for less than $US 2000. A
>low-duty cycle unit would be fine
I mostly listen and pounce, and don?t do
>contests
I just want it to be there when needed.
>
>Any help much appreciated.
>
>73
>Rod Elliott VE3IRF
>
>
>
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>Amps mailing list
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>http://lists.contesting.com/mailman/listinfo/amps
>
- R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K,
www.vcnet.com/measures.
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